Antimicrobial superabsorbent compositions and methods

ABSTRACT

An antimicrobial superabsorbent composition of a cross-linked hydrophilic sodium salt form of a partially neutralized acrylic acid-based polymer gel having covalently bonded thereto a silane. The composition can be in the form of flakes, strips, powders, filaments, fibers, or films, and may be applied to a substrate in the form of a coating.

BACKGROUND OF THE INVENTION

This invention relates to compositions, methods of treatment, andarticles of manufacture, wherein there is employed an antimicrobialsuperabsorbent formed of a cross-linked hydrophilic sodium salt form ofa partially neutralized acrylic acid-based polymer gel having covalentlybonded thereto a silane, for the purpose of providing the benefits ofodor reduction, control of microbes, and reduction of microbial rashesand allergies.

Antimicrobial agents are chemical compositions that are used to preventmicrobiological contamination and deterioration of products, materials,and systems. Particular areas of application of antimicrobial agents andcompositions are, for example, cosmetics, disinfectants, sanitizers,wood preservation, food, animal feed, cooling water, metalworkingfluids, hospital and medical uses, plastics and resins, petroleum, pulpand paper, textiles, latex, adhesives, leather and hides, and paintslurries. Of the diverse categories of antimicrobial agents andcompositions, quaternary ammonium compounds represent one of the largestof the classes of antimicrobial agents in use. At low concentrations,quaternary ammonium type antimicrobial agents are bacteriostatic,fungistatic, algistatic, sporostatic, and tuberculostatic. At mediumconcentrations they are bactericidal, fungicidal, algicidal, andviricidal against lipophilic viruses. Silicone quaternary ammonium saltcompounds are well known as exemplified by U.S. Pat. No. 3,560,385, andthe use of such compounds as antimicrobial agents is taught, forexample, in a wide variety of patents such as U.S. Pat. Nos. 3,730,701,and 3,817,739, where the compounds are used to inhibit algae; 3,794,736;3,860,709; 3,865,728, where the compounds are used to treat aquariumfilters; 4,259,103; and in British Patent No. 1,386,876. Publishedunexamined European Application No. 228464 of July 15, 1987, teachesthat microorganisms on plants can be killed by the application theretoof an aqueous mixture of a surfactant and an organosilicon quaternaryammonium compound. In a particular application of an antimicrobialsilicone quaternary ammonium compound, a paper substrate is renderedresistant to the growth of microorganisms in U.S. Pat. No. 4,282,366. InU.S. Pat. No. 4,504,541, an antimicrobial fabric is disclosed which isresistant to discoloration and yellowing by treatment of the fabric witha quaternary ammonium base containing an organosilicone. U.S. Pat. No.4,615,937, as well as its companion U.S. Pat. No. 4,692,374, relate towet wiper towelettes having an antimicrobial agent substantive to thefibers of the web and being an organosilicon quaternary ammoniumcompound. Thus, the versatility of such compositions is readilyapparent.

Absorbent polymers capable of absorbing from about thirty to sixty gramsof water per gram of polymer are known, as is the use of such polymersin disposable diapers, sanitary napkins, surgical pads, and bath mats,for example. A particularly sought-after property is increased waterabsorbency. Polymers having this property often are referred to ashydrogels or superabsorbents. The nature and utility of superabsorbentsare illustrated by U.S. Pat. No. 4,449,977. According to this reference,a desirable feature of a superabsorbent is the presence of acrylate ormethacrylate groups which can be salts, amides, esters, or the freeacids. Many hydrogels are based on acrylate and methacrylate polymersand copolymers, for example, as shown in U.S. Pat. Nos. 2,976,576,3,220,960, 3,993,616, 4,154,898, 4,167,464, 4,192,727, 4,192,827, and4,529,739. Hydrogels based on starch or a modified starch are shown byU.S. Pat. Nos. 4,069,177, 4,076,663, 4,115,332, and 4,117,222. Otherhydrogels are based on poly(oxyalkylene) glycols as in U.S. Pat. No.3,783,872. Hydrogels prepared from hydrolyzed crosslinkedpolyacrylamides and crosslinked sulfonated polystyrenes are described inU.S. Pat. No. 4,235,237. Finally, polymers based on maleic anhydridehave been described in U.S. Pat. Nos. 2,988,539, 3,393,168, 3,514,419,3,557,067, and 4,401,793. U.S. Pat. No. 3,900,378 describes hydrogelsfrom radiation crosslinked blends of hydrophilic polymers and fillers.Such category of absorbent polymers preferred in the present invention,however, can be exemplified by, for example, U.S. Pat. No. 3,966,679,which relates to acrylic acid based water swellable super absorbentpolymers useful as catamenial tampons and diapers. Such absorbentpolymers that possess, in addition to their superabsorbencycharacteristics, the property of antimicrobial activity, are not known,however. Therefore, in accordance with the present invention, it hasbeen found that superabsorbent compositions which have antimicrobialproperties can be formed, which possess the characteristics andadvantages of both categories of the silicone quaternary ammonium saltsas well as the acrylic acid based water swellable super absorbentpolymer compositions noted above. Thus, in addition to absorbing largequantities of fluids, the compositions of the present invention act inpreventing microbiological contamination and deterioration of products,materials, and systems. For example,3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride, hereinafterreferred to as TMS, is an effective antimicrobial agent in which theactive ingredient hydrolyzes in water and reacts with substrates withwhich it is brought into contact. These substrates demonstratenonleaching broad spectrum antimicrobial activity. By including anantimicrobial component in the water swellable absorbent composition,the benefits of both compositions are realized as against bothfunctioning independently one from the other. Hence, the compositionsset forth in the present invention possess unique features andadvantages over existing antimicrobial treating agents and hydrophilicgels and provide improved results thereover. Thus, the disadvantages ofthe prior art are overcome with the present invention wherein improvedantimicrobial agents are provided.

SUMMARY OF THE INVENTION

This invention relates to an antimicrobial superabsorbent composition ofa cross-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer gel having covalently bonded thereto a silaneof the general formula

    Y.sub.3 SiRN.sup.+ R'R"R'"X.sup.-

where Y denotes a hydrolyzable radical, R denotes a divalent hydrocarbonradical with 1 to 6 carbon atoms, R', R" and R'" independently denotesaturated or unsaturated hydrocarbon radicals containing 1 to 18 carbonatoms, saturated or unsaturated organic radicals consisting of carbon,hydrogen and oxygen; carbon, hydrogen, and sulfur; or carbon, hydrogenand nitrogen, and X denotes an anion.

The silane can also be represented by the general formula

    Y.sub.3 Si(CH.sub.2).sub.m N.sup.+ (CH.sub.3).sub.2 (CH.sub.2).sub.n CH.sub.3 X.sup.-

where Y denotes a hydrolyzable radical, X denotes an acid anion, andwhere m+n is 16 to 23, m is 1 to 11, and n is 9 to 17. Specific examplesof compounds included thereunder are, for example, the silanerepresented by the formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-

and the silane represented by the formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (C.sub.10 H.sub.21).sub.2 (CH.sub.3)Cl.sup.-

The invention also relates to a method of inhibiting the proliferationof potentially destructive microorganisms on a substrate by treating thesubstrate with an effective amount of an antimicrobial superabsorbentcomposition formed of a cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer gel having covalentlybonded thereto a silane of the general formula

    Y.sub.3 SiRN.sup.+ R'R"R'"X.sup.-

where Y denotes a hydrolyzable radical, R denotes a divalent hydrocarbonradical with 1 to 6 carbon atoms, R', R" and R'" independently denotesaturated or unsaturated hydrocarbon radicals containing 1 to 18 carbonatoms, saturated or unsaturated organic radicals consisting of carbon,hydrogen and oxygen; carbon, hydrogen, and sulfur; or carbon, hydrogenand nitrogen, and X denotes an anion. The composition can be in the formof flakes, strips, powders, filaments, fibers, or films.

The invention further relates to a method of reducing odor andsimultaneously controlling diaper rash by the suppresion of bacteriathat attack urinary urea with the liberation of ammonia by impregnatingthe diaper fabric with an effective amount of a composition forcontrolling the spread of infection, the composition being anantimicrobial superabsorbent formed of a cross-linked hydrophilic sodiumsalt form of a partially neutralized acrylic acid-based polymer gelhaving covalently bonded thereto a silane of the general formula

    Y.sub.3 SiRN.sup.+ R'R"R'"X.sup.-

where Y denotes a hydrolyzable radical, R denotes a divalent hydrocarbonradical with 1 to 6 carbon atoms, R', R" and R'" independently denotesaturated or unsaturated hydrocarbon radicals containing 1 to 18 carbonatoms, saturated or unsaturated organic radicals consisting of carbon,hydrogen and oxygen; carbon, hydrogen, and sulfur; or carbon, hydrogenand nitrogen, and X denotes an anion.

It is therefore an object of the present invention to providecompositions, methods of treatment, and articles of manufacture, whereinthere is employed an antimicrobial superabsorbent formed of across-linked hydrophilic sodium salt form of a partially neutralizedacrylic acid-based polymer gel having covalently bonded thereto asilane.

It is also an object of the present invention to provide compositions,methods of treatment, and articles of manufacture, wherein there isemployed an antimicrobial superabsorbent formed of a cross-linkedhydrophilic sodium salt form of a partially neutralized acrylicacid-based polymer gel having covalently bonded thereto a silane for thepurpose of providing the benefits of odor reduction, control ofmicrobes, and reduction of microbial rashes and allergies.

These and other features, objects, and advantages, of the presentinvention will become apparent from the following detailed descriptionof the invention.

DETAILED DESCRIPTION OF THE INVENTION

The compositions of the present invention were prepared in accordancewith the Examples set forth hereinbelow, and in the Examples as well asin the Tables tabulating results thereof, the composition identified asTMS refers to a product manufactured by the Dow Corning Corporation asan antimicrobial agent and is3-(trimethoxysilyl)-propyloctadecyldimethyl ammonium chloride diluted toforty-two percent active ingredients by weight with methanol, and havingthe formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-

The material DRYTECH® is a product manufactured by the Dow ChemicalCompany and is a water swellable absorbent of a carboxylicpolyelectrolyte. This cross-linked hydrophilic sodium salt form of apartially neutralized acrylic acid-based polymer gel can be prepared bythe techniques described, for example, in U.S. Pat. No. 3,966,679,issued June 29, 1976, to James R. Gross, and assigned to the DowChemical Company. The materials DRYTECH® and TMS are otherwise combinedand reacted together in order to form a covalent bond therebetween.

The polymeric material DRYTECH® absorbs and holds large amounts of waterin a gel-like matrix. This gel, however, is an ideal situs formicroorganisms when some type of nutrient is supplied. For example, indiapers and sanitary pads, fluids are absorbed which contain heavyorganic loads of potential nutrients resulting in an ideal environmentfor microbial growth. This can be offset by incorporating into theabsorbent polymer in a covalent bonding relationship an antimicrobialagent such as TMS thereby producing an otherwise antimicrobialsuperabsorbent. The antimicrobial agent can be incorporated by additionof the agent to the absorbent polymer during its manufacture, or byaddition of the agent to the absorbent polymer following its manufactureas a treated filler or by a non-aqueous treatment of the absorbentpolymer with the agent in toluene. It has been found that even thoughthe antimicrobial agent may be classified as a hydrophobing agent, itdoes not function in the fashion of reducing the absorbent capacity ofthe polymer. In fact, the gel strength of the absorbent polymer as wellas its salt tolerance are improved. In diapers and sanitary padscontaining the compositions of the present invention, it has been foundthat such items possess the added benefits of reduced odor, improvedcontrol of microbes, and the reduction of microbial rashes andallergies.

The anion of an aqueous sodium salt of bromphenol blue can be complexedwith the cation of a polymerized silane of this invention while it is ona substrate. The blue colored complex, substantive to a water rinse, isqualitatively indicative of the presence of the cation on the substratethus indicating the extent of antimicrobial agent on a given substrate.A comparison of the intensity of retained blue color to a color standardis used as a check to determine if the treatment has been appliedproperly.

The method consists of preparing a 0.02 to 0.04 weight percent solutionof bromphenol blue in distilled water. This solution is made alkalineusing a few drops of saturated Na₂ CO₃ solution per 100 milliliters ofthe solution. Two to three drops of this solution are placed on thetreated substrate and allowed to stand for two minutes. The substrate isthen rinsed with copious amounts of tap water and the substrate isobserved for a blue stain and it is compared to a color standard.

For a spectrophotometric determination, the following test is used.

The sodium salt of bromphenol blue is depleted from a standard solutionby complexing with the cations on a treated substrate. The change inbromphenol blue concentration is determined spectrophotometrically or bycomparison with color standards whereby the level of substrate treatmentby the cationic silane is determinable.

The method consists of preparing a 0.02 weight percent standard solutionof bromphenol blue in distilled water. It is made alkaline with a fewdrops of saturated Na₂ CO₃ solution per 100 milliliters of bromphenolblue solution. The color of this solution is purple.

The blank solution is adjusted to yield a 10 to 12% transmittancereading when measured in 1 cm cells using a spectrophotometer set at 589nm by the following method.

Fill a container 3/4 full of distilled water and add 2 ml of the 0.02%standard bromphenol blue solution for every 50 ml of distilled water.Add 0.5 ml of a 1% Triton® X-100 surfactant (manufactured by Rohm andHaas, Philadelphia, PA, USA) aqueous solution for every 50 ml of water.Mix, and using the spectrophotometer, determine the maximum absorbance.Adjust the upper zero to 100% transmittance with distilled water. Checkthe percent transmittance of the working bromphenol blue solution at themaximum absorbance setting. Adjust the blank solution to 10 to 12%transmittance with either water or bromphenol blue standard solution asnecessary.

The samples of treated substrate are tested by placing 0.5 gram samplesof the substrate standards in a flask large enough for substantialagitation of the sample and the test solution. Add 50 ml of the workingsolution. Agitate for 20 minutes on a wrist-action shaker. Fill the testcurvette with the test solution. Centrifuge if particulate matter ispresent. Measure the % transmittance at the wavelength set forth above.The transmittance is compared against a standard curve prepared bypreparing several substrate samples of known concentration of thecationic silane. For example, samples containing a known amount ofcationic silane at, for example, 0%, 0.25%, 0.50%, 0.75% and 1% are readspectrophotometrically and a curve is plotted.

The silanes useful in this invention also have the general formula##STR1## It should be noted that generically, these materials arequaternary ammonium salts of silanes. Most of the silanes falling withinthe scope of this invention are known silanes and references disclosingsuch silanes are numerous. One such reference, U.S. Pat. No. 4,259,103,issued to James R. Malek and John L. Speier, on Mar. 31, 1981, discussesthe use of such silanes to render the surfaces of certain substratesantimicrobial. Canadian Patent No. 1,010,782, issued to Charles A. Rothshows the use of fillers treated with certain silanes to be used inpaints and the like to give antimicrobial effects.

Numerous other publications have disclosed such silanes, namely, A. J.Isquith, E. A. Abbott and P. A. Walters, Applied Microbiology, Dec.1972, pages 859-863; P. A. Walters, E. A. Abbott and A. J. Isquith,Applied Microbiology, 25, No. 2, p. 253-256, Feb. 1973 and E. A. Abbottand A. J. Isquith, U.S. Pat. No. 3,794,736 issued Feb. 26, 1974, U.S.Pat. No. 4,406,892, issued Sept. 27, 1983, among others.

For purposes of this invention, the silanes can be used neat or they canbe used in solvent or aqueous-solvent solutions. When the silanes areused neat, the inventive process is preferably carried out in a systemin which some small amount of water is present. If it is not possible tohave a system with some small amount of water present, then a watersoluble or water-dispersable, low molecular weight hydrolyzate of thesilane may be used. What is important is the fact that the durability ofany effect produced by the silane as part of a product requires that thesilane molecule react with a surface to a certain extent. The mostreactive species, as far as the silanes are concerned, is the .tbd.SiOHthat is formed by hydrolysis of the alkoxy groups present on the silane.The .tbd.SiOH groups tend to react with the surface and bind the silanesto the surface. It is believed by the inventor even though the primemode of coupling to the surface system is by the route described above,it is also believed by the inventor that the alkoxy groups on thesilicon atom may also participate in their own right to bind to thesurface.

Preferred for this invention is a reactive surface containing some smallamount of water. By "reactive", it is meant that the surface mustcontain some groups which will react with some of the silanols generatedby hydrolysis of the silanes of this invention.

R in the silanes of this invention are alkyl groups of 1 to 4 carbonatoms. Thus, useful as R in this invention are the methyl, ethyl, propyland butyl radicals. R can also be hydrogen thus indicating the silanolform, i.e. the hydrolyzate. The value of a is 0, 1 or 2 and R' is amethyl or ethyl radical.

R" for purposes of this invention is an alkylene group of 1 to 4 carbonatoms. Thus, R" can be alkylene groups such as methylene, ethylene,propylene, and butylene. R'", R"", and R^(v) are each independentlyselected from a group which consists of alkyl radicals of 1 to 18carbons, --CH₂ C₆ H₅, --CH₂ CH₂ OH, --CH₂ OH, and --(CH₂)_(x)NHC(O)R^(vi). x has a value of from 2 to 10 and R^(vi) is aperfluoroalkyl radical having from 1 to 12 carbon atoms. X is chloride,bromide, fluoride, iodide, acetate or tosylate.

Preferred for this invention are the silanes of the general formula##STR2## R is methyl or ethyl; a has a value of zero; R" is propylene;R'" is methyl or ethyl; R"" and R^(v) are selected from alkyl groupscontaining 1 to 18 carbon atoms wherein at least one such group islarger than eight carbon atoms and x is either chloride, acetate ortosylate.

Most preferred for this invention are those silanes having the formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.⊕ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-

    and

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.⊕ CH.sub.3 (C.sub.10 H.sub.21).sub.2 Cl.sup.-.

As indicated above, most of these silanes are known from the literatureand methods for their preparation are known as well. See, for example,U.S. Pat. No. 4,282,366, issued Aug. 4, 1981; U.S. Pat. No. 4,394,378,issued July 19, 1983, and U.S. Pat. No. 3,661,963 issued May 9, 1972,among others.

Specific silanes within the scope of the invention are represented bythe formulae:

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Br.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (C.sub.10 H.sub.21).sub.2 CH.sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (C.sub.10 H.sub.21).sub.2 CH.sub.3 Br.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 P.sup.+ (C.sub.6 H.sub.5).sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 P.sup.+ (C.sub.6 H.sub.5).sub.3 Br.sup.-,

    (CH.sub.3 O).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 P.sup.+ (CH.sub.3).sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 P.sup.+ (C.sub.6 H.sub.13).sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.4 H.sub.9 Cl.sup.-,

    (C.sub.2 H.sub.5 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 CH.sub.2 C.sub.6 H.sub.5 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 CH.sub.2 CH.sub.2 OHCl.sup.-,

    (HO).sub.3 Si(CH.sub.2).sub.3 N.sup.+ PhCl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 ##STR3##

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 (CH.sub.2).sub.3 NHC(O)(CF.sub.2).sub.6 CF.sub.3 Cl.sup.-,

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (C.sub.2 H.sub.5).sub.3 Cl.sup.-.

X is chlorine in the above structures.

The compositions of the present invention have a wide range ofapplication including, for example but not limited to, bandages,surgical tampons, sorptive dental rolls, catamenial tampons, sanitarynapkins, diapers, body urinals, underarm perspiration pads, breast pads,disposable hat bands, disposable wiping cloths, tissue wipes,pre-moistened towelettes, mattress pads, undersheets, dressings, facialtissues, and of woven or unwoven materials and fabrics such as cotton,cloth, rayon, nylon, wool, surgical gauze, burlap, or paper.

EXAMPLE I

A mixture of five percent by weight of treated CAB-O-SIL® andninety-five percent by weight of DRYTECH® was prepared by combining in acontainer 19.17 grams of DRYTECH® and 1.0 grams of CAB-O-SIL®pre-treated with one percent by weight of TMS. The material CAB-O-SIL®is colloidal silica particles manufactured by Cabot Corporation, Kokomo,Ind. The ingredients were thoroughly mixed together in the container,and blended with a magnetic stirrer on a hot plate set at low heat whilemaintaining agitation for thirty minutes. The product from the containerwas allowed to cool and gravity filtered, and allowed to dry overnightat room temperature. The resulting powder in an amount of 0.5 grams wasplaced in fifty milliliters of bromophenol blue standard solution andagitated for about twenty minutes. Observations were made based oncolor, and the color was found to be purple-blue. The gel was dried toremove moisture, and the powder was rinsed with toluene to determine ifthe treatment was durable. No purple-blue color was found to have beenremoved by the toluene indicating that the treatment was durable.

EXAMPLE II

A mixture of ten percent by weight of treated CAB-O-SIL® and ninetypercent by weight of DRYTECH® was prepared by combining in a container22.5 grams of DRYTECH® and 2.5 grams of CAB-O-SIL® pre-treated with onepercent by weight of TMS. The ingredients were thoroughly mixed togetherin the container, and blended with a magnetic stirrer on a hot plate setat low heat while maintaining agitation for thirty minutes. The productfrom the container was allowed to cool and gravity filtered, and allowedto dry overnight at room temperature. The resulting powder in an amountof 0.5 grams was placed in fifty milliliters of bromophenol bluestandard solution and agitated for about twenty minutes. Observationswere made based on color, and the color was found to be blue. The gelwas dried to remove moisture, and the powder was rinsed with toluene todetermine if the treatment was durable. No blue color was found to havebeen removed by the toluene indicating that the treatment was durable.

EXAMPLE III

A mixture of five percent by weight of treated aluminum chlorohydrateand ninety-five percent by weight of DRYTECH® was prepared by combiningin a container 19.06 grams of DRYTECH® and 2.12 grams of aluminumchlorohydrate pre-treated with one percent by weight of TMS. Theingredients were thoroughly mixed together in the container, and blendedwith a magnetic stirrer on a hot plate set at low heat while maintainingagitation for thirty minutes. The product from the container was allowedto cool and gravity filtered, and allowed to dry overnight at roomtemperature. The resulting powder in an amount of 0.5 grams was placedin fifty milliliters of bromophenol blue standard solution and agitatedfor about twenty minutes. Observations were made based on color, and thecolor was found to be purple.

EXAMPLE IV

A mixture was prepared by combining in a container 134.44 grams oftoluene, 19.34 grams of DRYTECH®, and 2.42 grams of TMS. The ingredientswere thoroughly mixed together in the container, and blended with amagnetic stirrer on a hot plate set at low heat while maintainingagitation for thirty minutes. The product from the container was allowedto cool and gravity filtered, and allowed to dry overnight at roomtemperature. The resulting powder in an amount of 0.5 grams was placedin fifty milliliters of bromophenol blue standard solution and agitatedfor about twenty minutes. Observations were made based on color, and thecolor was found to be blue. The powder was dried, rinsed with tolueneand found durable as in Example II.

EXAMPLE V

A mixture was prepared by combining in a container 134.44 grams ofToluene, 20.0 grams of DRYTECH®, and 0.125 grams of TMS. The ingredientswere thoroughly mixed together in the container, and blended with amagnetic stirrer on a hot plate set at low heat while maintainingagitation for thirty minutes. The product from the container was allowedto cool and gravity filtered, and allowed to dry overnight at roomtemperature. The resulting powder in an amount of 0.5 grams was placedin fifty milliliters of bromophenol blue standard solution and agitatedfor about twenty minutes. Observations were made based on color, and thecolor was found to be purple-blue. The gel was dried to remove moisture,and the powder was rinsed with toluene to determine if the treatment wasdurable as to the absorbent polymer. No purple-blue color was found tohave been removed by the toluene indicating that the treatment wasdurable.

EXAMPLE VI

A mixture was prepared by combining in a container 134.44 grams ofToluene, 20.0 grams of DRYTECH®, and 2.5 grams of TMS. The ingredientswere thoroughly mixed together in the container, and blended with amagnetic stirrer on a hot plate set at low heat while maintainingagitation for thirty minutes. The product from the container was allowedto cool and gravity filtered, and allowed to dry overnight at roomtemperature. The resulting powder in an amount of 0.5 grams was placedin fifty milliliters of bromophenol blue standard solution and agitatedfor about twenty minutes. Observations were made based on color, and thecolor was found to be blue. The gel was dried to remove moisture, andthe powder was rinsed with toluene to determine if the treatment wasdurable as to the absorbent polymer. No blue color was found to havebeen removed by the toluene indicating that the treatment was durable.

EXAMPLE VII

A mixture was prepared by combining in a container 134.44 grams ofToluene, 20.0 grams of DRYTECH®, and 5.0 grams of TMS. The ingredientswere thoroughly mixed together in the container, and blended with amagnetic stirrer on a hot plate set at low heat while maintainingagitation for thirty minutes. The product from the container was allowedto cool and gravity filtered, and allowed to dry overnight at roomtemperature. The resulting powder in an amount of 0.5 grams was placedin fifty milliliters of bromophenol blue standard solution and agitatedfor about twenty minutes. Observations were made based on color, and thecolor was found to be blue. The gel was dried to remove moisture, andthe powder was rinsed with toluene to determine if the treatment wasdurable as to the absorbent polymer. No blue color was found to havebeen removed by the toluene indicating that the treatment was durable.

A control sample of DRYTECH® when treated alone in accordance with theforegoing procedures rendered a purple color.

                  TABLE I                                                         ______________________________________                                        EXAM-                                                                         PLE    DRYTECH ®                                                                             CAB-O-SIL ®                                                                           TMS   COLOR                                    ______________________________________                                        1      *           *D          *     purple-blue                              2      *           *D          *     blue                                     3      *           A, D        *     purple                                   4      *B, D       C           *     blue                                     5      *B, D       C           *     purple-blue                              6      *B, D       C           *     blue                                     7      *B, D       C           *     blue                                     Control                                                                              C           C           C     purple                                   ______________________________________                                         A = CABO-SIL ® replaced with aluminum chlorohydrate.                      B = Toluene treated.                                                          C = No ingredient included.                                                   D = TMS durably bound.                                                        Control = DRYTECH                                                             * = Ingredient included.                                                 

A consideration of the foregoing results of the treated materials bybromophenol blue analytical analysis tabulated and set forth in Table Iindicates that the treatments with the antimicrobial agent in Examples2, 4, 6, and 7, were highly effective as evidenced by the blue color;that the treatments with the antimicrobial agent in Examples 1 and 5were moderately effective as evidenced by the purple-blue color; andthat the treatment evidencing a purple color was of little or no effect,including the control sample.

The antimicrobial activity of a treated surface is evaluated by shakinga sample weighing 0.75 grams in a 750,000 to 1,500,000 count Klebsiellapneumoniae suspension for a one hour contact time. The suspension isserially diluted, both before and after contact, and cultured. Thenumber of viable organisms in the suspensions is determined. The percentreduction based on the original count is determined. The method isintended for those surfaces having a reduction capability of 75 to 100%for the specified contact time. The results are reported as the percentreduction.

Media used in this test are nutrient broth, catalog No. 0003-01-6 andtryptone glucose extract agar, catalog No. 0002-01-7 both available fromDifco Laboratories, Detroit, Mich., U.S.A. The microorganism used isKlebsiella pneumoniae American Type Culture Collection; Rockville, Md.U.S.A., catalog No. 4352.

The procedure used for determining the zero contact time counts iscarried out by utilizing two sterile 250 ml. screw-cap Erlenmeyer flasksfor each sample. To each flask is added 70 ml of sterile buffersolution. To each flask is added, aseptically, 5 ml of the organisminoculum. The flasks are capped and placed on a wrist action shaker.They are shaken at maximum speed for 1 minute. Each flask is consideredto be at zero contact time and is immediately subsampled by transferring1 ml of each solution to a separate test tube containing 9 ml of sterilebuffer. The tubes are agitated with a vortex mixer and then 1 ml of eachsolution is transferred to a second test tube containing 9 ml of sterilebuffer. Then, after agitation of the tubes, 1 ml of each tube istransferred to a separate sterile petri dish. Duplicates are alsoprepared. Sixteen ml of molten (42° C.) tryptone glucose extract agar isadded to each dish. The dishes are each rotated ten times clockwise andten times counterclockwise. The dishes are then incubated at 37° C. for24 to 36 hours. The colonies are counted considering only those between30 and 300 count as significant. Duplicate samples are averaged. Theprocedure used for determining the bacterial count after 1 hour isessentially the same as that used to determine the count at the zerocontact time. The only difference is that pour plating is performed atthe 10⁰ and 10⁻¹ dilutions as well as at the 10⁻² dilution. "Percentreduction" is calculated by the formula ##EQU1## where A is the countper milliliter for the flask containing the treated substrate; B is zerocontact time count per milliliter for the flask used to determine "A"before the addition of the treated substrate and C is zero contact timecount per milliliter for the untreated control substrate.

The microbiological efficacy of the compositions of the presentinvention was determined as noted above. The antimicrobial activity oftreated surfaces of the compositions was, however, evaluated by shakingsamples in a 750,000 to 1,500,000 count Escherichia coli and Klebsiellapneumoniae suspension for a one hour contact time. The suspension wasserially diluted both before and after contact and cultured. The numberof viable organisms in the suspensions was determined. The percentreduction based on the original count was also determined. The resultsand data of the antimicrobial activity dynamic surface testing conductedare set forth in the Tables II and III hereinbelow and indicating thatthe compositions are antimicrobially active in their nature andfunction, in addition to performing as superabsorbent materials, andthat the microorganisms were substantially reduced in number.Accordingly, the antimicrobial activity of the compositions of thepresent invention was rated excellent.

In the Tables, the growth was rated from (-) for no growth, (+) for1-100 colonies, (++) for 100-300 colonies, and (+++) for colonies toonumerous to count. The test system employed consisted of seventy-fivemilliliters of diluent pre-inoculated with approximately 15,000 CFU permilliliter. Samples to be tested were added at the rate of one-half ofone gram per seventy-five milliliters. Standardized sub-samples wereprepared with a sterile swab and plated on TGE agar.

                  TABLE II                                                        ______________________________________                                        ESCHERICHIA COLI                                                              PHOSPHATE BUFFER                                                                      TIME IN HOURS                                                         SAMPLE    0             1       24                                            ______________________________________                                        4         +++           +++     +++                                           5         +++           +++     +++                                           6         +++           +++     ++                                            7         +++           +++     +                                             Control   +++           +++     +++                                           TMS       +++           +++     +                                             ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        KLEBSIELLA PNEUMONIAE                                                         PHOSPHATE BUFFER     0.85% SALINE                                             TIME IN HOURS        TIME IN HOURS                                            SAMPLE  0       1        24    0     1     24                                 ______________________________________                                        4       +++     +++      +++   +++   +++   +++                                5       +++     +++      +     +++   +++   +++                                6       +++     +++      +     +++   +++   +                                  7       +++     +++      +     +++   +++   +                                  Control +++     +++      +++   +++   +++   +++                                TMS     +++     +        +     +++   +++   +                                  ______________________________________                                    

It will be apparent from the foregoing that many other variations andmodifications may be made in the structures, compounds, compositions,articles of manufacture, and methods described herein without departingsubstantially from the essential features and concepts of the presentinvention. Accordingly, it should be clearly understood that the formsof the invention described herein are exemplary only and are notintended as limitations on the scope of the present invention.

That which is claimed is:
 1. An antimicrobial superabsorbent compositioncomprising a water absorbing cross-linked hydrophilic sodium salt formof a partially neutralized acrylic acid-based polymer gel havingcovalently bonded thereto an organosilane, the organosilane beingpresent in an amount to prevent hydrophobing and reduction of theabsorbent capacity of the polymer gel, the organosilane having thegeneral formula selected from the group consisting of ##STR4## wherein,in each formula, R is an alkyl radical of 1 to 4 carbon atoms orhydrogen;a has a value of 0, 1 or 2; R' is a methyl or ethyl radical; R"is an alkylene group of 1 to 4 carbon atoms; R'", R"" and R^(v) are eachindependently selected from a group consisting of alkyl radicals of 1 to18 carbon atoms, --CH₂ C₆ H₅, --CH₂ CH₂ OH, --CH₂ OH, and --(CH₂)_(x)NHC(O)R^(vi), wherein x has a value of from 2 to 10 and R^(vi) is aperfluoroalkyl radical having from 1 to 12 carbon atoms; and X ischloride, bromide, fluoride, iodide, acetate or tosylate.
 2. Thecomposition of claim 1 wherein the organosilane is represented by theformula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (CH.sub.3).sub.2 C.sub.18 H.sub.37 Cl.sup.-


3. The composition of claim 1 wherein the organosilane is represented bythe formula

    (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 N.sup.+ (C.sub.10 H.sub.21).sub.2 (CH.sub.3)Cl.sup.-


4. The composition of claim 1 in the form of flakes, strips, powders,filaments, or fibers.